Firearms comprise a class of machines that have special requirements for their cleaning and maintenance. While firearms may be used in peaceful settings, for sporting events and the like, firearms are also relied upon to protect and defend the lives of military and law enforcement, as well as civilians placed in the protection of armed personnel. As such, reliable operation of the firearm is of ultimate importance. Regularly scheduled specialized cleaning and maintenance procedures are required to insure such performance.
Firearms typically employ a number of inter-fitting mechanisms and components that are machined with close tolerances. Firearms accordingly require cleaning for the same reasons associated with other types of precision machines. As a mechanism is operated, certain parts may tend to wear, and thereby create material which would foul or otherwise hinder smooth operation of the various moving parts. In addition, firearms rely on the ignition or combustion of propellants broadly referred to as “gunpowder.” In times past, this material was made in the form of a powder, with individual particles assuming a ball shape. More recently, so-called “stick” and flake powders have been developed. In stick powders, for example, particles of the combustible propellants are extruded in the form of short, small-sized cylinders or “sticks.” Each type of propellant burns differently and has its own types of combustion products.
In modern usage, propellants are contained within a brass or nickel case to which is fitted a primer to initiate ignition of the propellant, and a bullet or other projectile to be launched from the firearm. Ignition typically occurs with the propellant located within a closed firing chamber where substantial pressure levels are developed by rapid gas expansion of the propellant. Once developed, pressure from the propellant gases is applied against the projectile, forcing the projectile to travel along the barrel until the projectile exits at the muzzle of the barrel.
A number of firearms in popular use today are based on a design originally adopted by the U.S. Military under the “M16” designation. Today, several variants of this design are in production and use. In broad terms, this type of firearm includes a gas operated automatic loading feature, powered by diverting a portion of the energy developed from ignition of the propellant, back to the operating mechanism. This provides power for a number of functions that are automatically performed from the firing of one round to the next.
In the automatic, gas powered firearm operation considered here, ignition or oxidation of the propellant causes a rapid expansion of gases resulting from its ignition. Unfortunately, such ignition is typically incomplete, and takes place over a finite period of time during which a portion of the propellant is consumed. As mentioned, the gases produced by ignition propel the projectile down the barrel of the firearm. Unburnt propellant and combustion products are also carried by the gas stream, and follow the projectile during its trip down the firearm barrel. During this time, additional quantities of propellant are ignited in the barrel, further adding to the propulsion forces pushing the projectile toward the barrel muzzle. In the M16 family of firearms, for example, a port located in the firearm barrel, adjacent the muzzle, diverts a portion of the exiting gas (and particles contained therein) to perform automatic cycling action of various mechanisms associated with the firearm. For example, the diverted gas pressure is used to eject a casing from the firing chamber while loading a fresh cartridge into the firing chamber. Gas pressure is also used to force a movable bolt into position to enclose the firing chamber, providing a pressure-tight seal that resists the violent pressure rise of the propellant within the firing chamber.
Unfortunately, while pressure operated cycling has proven successful for its intended purpose, combustion products, including unburnt propellant and other undesirable contaminants, are carried within the gas stream, being brought into contact with close tolerance movable mechanisms for which automatic operation is desired. This contamination, sometimes referred to as “fouling,” necessitates regular cleaning as part of a routine maintenance procedure that insures reliable operation of the firearm. A problem arises however, since gas pressures and contaminants carried by those pressures are made to travel increasingly miniaturized tubular passageways.